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Detailed Reference Information |
Thomson, J., Colley, S., Anderson, R., Cook, G.T., MacKenzie, A.B. and Harkness, D.D. (1993). Holocene sediment fluxes in the Northeast Atlantic from 230Thexcess and radiocarbon measurements. Paleoceanography 8. doi: 10.1029/93PA01366. issn: 0883-8305. |
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Radiocarbon and 230Thexcess data from six NE Atlantic box cores are considered. The cores form a transect from the Porcupine Abyssal Plain over the East Thulean Rise to the southern end of Feni Drift. The chronology for the cores is established from bulk sediment carbonate radiocarbon data and reveals that sections exhibiting constant accumulation rates can be identified in all the cores, with rates of 3.0--3.5 cm kyr-1 on the plain through the Holecene and late Holocene rates of 4.3--6.6 cm kyr-1 elsewhere. Five out of the six cores show accumulations of more 230Thexcess than is produced in the overlying water column, with the greatest inventories (up to 225% of production) in the cores from the rise and drift. A size fraction comparison between two cores from the plain and rise reveals that the higher overall accumulation rates and 230Thexcess inventories in the off-plain cores are due to an increased fine (<5 μm) component fraction, whereas the flux of coarser material is similar to that received on the plain. This suggests that the hithr fluxes of materials observed are physically (rather than biogeochemically) driven and also that drift formation has been continuously active in the late Holocene. Sections of all the cores where regular accumulation is defined by the radiocarbon data are modeled first by a linear radiocarbon age/depth model and second by a constant rain 230Thexcess)0 model prorated fro the observed core inventories. These modeling approaches yield historical mass accumulation rate estimates which are generally in reasonable agreement (¿30%), but the differences observed appear to be well organized in time rather than random. |
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Abstract |
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Keywords
Oceanography, General, Paleoceanography, Oceanography, Biological and Chemical, Radioactivity and radioisotopes, Information Related to Geologic Time, Cenozoic |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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